package com.tsd.core.utils;

/**
 * @ClassName: LocationUtil
 * @Description: 地理位置工具类
 * @Author: Luoyc
 * @Date: 2020/3/30 19:22
 * @Version: 1.0
 */
public class LocationUtil {
    //地球半径，单位是千米
    private static final double EARTH_RADIUS = 6378.137;

    //将角度转换为弧度
    private static double rad(double d) {
        return d * Math.PI / 180.0;
    }

    /**
     * 通过经纬度获取距离(单位：米)
     *
     * @param lat1
     * @param lng1
     * @param lat2
     * @param lng2
     * @return
     */
    public static double getDistance(double lat1, double lng1, double lat2, double lng2) {
        double radLat1 = rad(lat1);
        double radLat2 = rad(lat2);
        double a = DoubleUtil.sub(radLat1, radLat2);
        double b = DoubleUtil.sub(rad(lng1), rad(lng2));
        double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2) + Math.cos(radLat1) * Math.cos(radLat2) * Math.pow(Math.sin(b / 2), 2)));
        s = s * EARTH_RADIUS;
        s = Math.round(s * 10000d) / 10000d;
        return Math.round(s * 1000d);
    }

    static public void main(String[] args) {
        double d = getDistance(40.049, 113.00009, 40.0497810000, 113);
        System.out.println(d);
    }
}
